Array lens, lighting optical system, optical unit and imaging apparatus

ABSTRACT

The present invention discloses the structure of the array lens that at least any one of the diagonal size, vertical size and lateral size of lens cell is set to almost 1/(4.5 or more) for each corresponding size of the display elements, the structure that the diagonal size of lens cell is set to almost 0.18 inch or less, the structure that the total number of lens cells is set to almost 240 or more and the structure that the lens focal distance of lens cell is set to almost 30 mm or less.

BACKGROUND OF THE INVENTION

[0001] Field of the Invention

[0002] The present invention relates to a technique of an apparatus fordisplaying images on a screen using a liquid crystal panel and an otherdisplay elements, for example, a liquid crystal projector, a reflectiontype image displaying projector, a liquid crystal television and aprojection type display apparatus.

[0003] A projection type imaging apparatus such as a liquid crystalprojector has been popular, in which the display element such as aliquid crystal panel or the like is irradiated with the light beamemitted from the light source and thereby an image on the displayelement can be projected as the enlarged image.

[0004] In the imaging apparatus of this type, the light from the lightsource is adjusted through conversion to gray scale of each pixel withthe display element and is then projected to the screen. For example, inthe case of the twisted nematic (TN) type liquid crystal display elementin which the display element is a typical example of the liquid crystaldisplay element, two sheets of polarizing plates are arranged to resultin difference of 90 degrees of polarizing directions before and afterthe liquid crystal cell which is formed by supplying the liquid crystalto the space between a couple of transparent substrates having thetransparent electrode films. In this case, amount of transmitting lightof the incident light beam is controlled to display the image ofinformation by combining the operations for rotating the polarizingplane with the electro-optical effect of the liquid crystal andselecting the polarizing element of the polarizing plate. In recentyears, such transmitting type or reflection type display element hasremarkably reduced in size of the element itself and also has improvedperformance such as resolution, etc.

[0005] Therefore, with advancement in size reduction and performance ofthe apparatus utilizing the display element, a projection type imagingapparatus has newly been proposed as the apparatus not only forrealizing image formation by video signal or the like which has beendone in the related art and but also for use as an image output deviceof a personal computer. The projection type imaging apparatus of thistype is particularly required to be small in size and to assure thatbright image can be obtained up to the corners of the display screen.

[0006] However, the projection type imaging apparatus of the related arthas problems that the apparatus size is large and brightness and qualityof image attained finally are insufficient.

[0007] For example, in the case of liquid crystal display apparatus,size reduction of the light bulb, namely liquid crystal element itselfis effective for size reduction of the apparatus as a whole, but whenthe liquid crystal display element is reduced in size, the areairradiated by the light of liquid crystal means becomes small, raising aproblem that a ratio in amount of light flux on the liquid crystaldisplay element for amount of total light flux radiated by the lightsource (hereinafter, referred to as light application efficiency)becomes lower and side area of display screen becomes dark. Moreover,since the liquid crystal display element can utilize the polarized lightbeam of only one direction, about a half of the light beam emitted fromthe light source which radiates the random polarized light beam is leftunused.

[0008] As a means for attaining the bright image at the four sides ofthe display screen, an integrator optical system, for example, has beenproposed, in which a couple of lenses are used as described in theJapanese Published Unexamined Patent Publication No. HEI 3-111806. Theintegrator optical system divides the light from the light source with aplurality of condenser lenses in the shape of the rectangular openingforming a first array lens and then focuses in overlapping the outputlight in the shape of rectangular opening at the radiating surface(liquid crystal display element) with a second array lens formed by thecondenser leans group corresponding to the condenser lenses in the shapeof rectangular opening. In this optical system, intensity distributionof the light irradiating the liquid crystal display element can bealmost equalized. Meanwhile, as the optical system for irradiating theliquid crystal display element with the light beam emitted from thelight source and arranged in one polarizing direction, a system isdisclosed in the Japanese Published Unexamined Patent Publication No.HEI 4-63318, in which the light beam emitted from the light source andis polarized at random is isolated to the P-polarized light beam andS-polarized light beam using the polarizing beam splitter and these arethen combined with a prism.

[0009] However, in the conventional integrator optical system, since adiagonal size of one lens cell of array lens is 0.25 inch or larger, anF value of the light system must be set to almost 2 or 3 in order toimprove equality of brightness and quality of image using the liquidcrystal display element with a micro-lens. As a result, distance betweenthe first and second array lenses becomes not shorter than 31 mm,disabling reduction in size of the optical system. Therefore, it hasbeen difficult for the projection type liquid crystal apparatus of therelated art to reduce the size of apparatus exceeding the size of the A4file size. Moreover, even in the optical system utilizing the polarizingbeam splitter, it is difficult to realize matching in accuracy in thearray lens and therefore size reduction has also been difficult. As aresult, it has been difficult to simultaneously realize reduction insize of the apparatus as a whole and improvement in performance such asbrightness. In addition, in the case of the projection type liquidcrystal apparatus, it has also been difficult, even when only thelighting means is improved, to attain the display apparatus which issmall in size and assures good display image quality because the imagequality depends on various factors, in addition to such lighting means,such as optical characteristic of objection leans and opticalcharacteristic of liquid crystal element.

[0010] Moreover, it has been required to use a larger array lens inorder to improve brightness in the integrator optical system of therelated art and when the projection type liquid crystal apparatus isreduced in size, brightness has been lowered. In addition, thisphenomenon can also be observed when size reduction is conducted in theoptical system using the polarizing beam splitter. As a result, it hasbeen difficult to simultaneously realize size reduction of the apparatusas a whole and improvement in performance such as brightness. Moreover,when a polarized beam combining means is used, performance deteriorationdue to unwanted light beam, namely the P-polarized light beam enteringthe S light path has also been observed.

SUMMARY OF THE INVENTION

[0011] It is therefore an object of the present invention to improvedisadvantages of the related art explained above, assure sufficientbrightness and good image quality and provide the image displaytechnique which enables higher accuracy and sufficient reduction in sizeof apparatus.

[0012] In order to attain the objects explained above, the presentinvention provides the structure that:

[0013] (1) an array lens is provided, in which at least any one of thediagonal size, vertical size and lateral size of lens cell is equal toalmost 1/(4.5 or more) for each corresponding size of a display elementwhich is irradiated by a lighting optical system;

[0014] (2) an array leans is provided, in which a diagonal size of lenscell is almost 0.18 inch or less;

[0015] (3) an array lens is provided, in which the total number of lenscells is almost 240 or more;

[0016] (4) an array lens is provided, in which the lens focal distanceof lens cell is 30 mm or less;

[0017] (5) a light shielding means is provided to eliminate unwantedlight beam to the light incident side than the light source unit orlight isolating means for isolating the light emitted from the arraylens to the P-polarized light beam and S-polarized light beam; and

[0018] (6) a first array lens for condensing the light from the lightsource unit to form a plurality of secondary light source image, asecond array lens for focusing a lens image of the first lens array lensto the display element, an isolating means for isolating the light beamemitted from the light source unit or from the array lens into theP-polarized light beam and S-polarized light beam, and a convertingmeans for changing any one beam of the P-polarized light beam andS-polarized light beam of the output light beam emitted from theisolating means are arranged almost on the same optical axis like thelinear line.

BRIEF DESCRIPTION OF THE DRAWINGS

[0019]FIG. 1 is a diagram illustrating a preferred embodiment of thepresent invention.

[0020]FIG. 2 is a diagram illustrating a structure of the apparatus as apreferred embodiment of the present invention.

[0021]FIG. 3 is a diagram explaining the effect of a preferredembodiment of the present invention.

[0022]FIG. 4 is a diagram illustrating a preferred embodiment of thepresent invention.

[0023]FIG. 5 is a diagram illustrating the other preferred embodiment ofthe present invention.

[0024]FIG. 6 is a diagram illustrating the other preferred embodiment ofthe present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] The preferred embodiments of the present invention will beexplained with reference to the accompanying drawings.

[0026]FIG. 1 illustrates a first preferred embodiment of the projectiontype liquid crystal display apparatus of the present invention. In FIG.1, the projection type liquid crystal display apparatus is provided witha light source 1. This light source 1 is formed of a super-high pressuremercury lamp, metal halide lamp, xenon lamp, mercury xenon lamp and awhite lamp such as halogen lamp. The light source 1 has at least onereflecting mirror 5 having a circular or polygonal light emittingaperture and an electrode wire 28 having the diameter, for example, of0.6 mm or less provided at one side of the lamp electrode in thereflecting mirror and the light beam emitted from this light source 1travels toward a projection lens 3 passing through a liquid crystaldisplay element 2 as a light bulb element and is then projected to ascreen 4.

[0027] The light beam radiated from a bulb of the light source 1 iscondensed by a reflector 5 having the elliptical surface, parabolicsurface or non-spherical surface and then enters a first array lens 6.After passing the first array lens 6, the light beam passes a secondarray lens 7 and then enters a polarized beam splitter 8. This incidentlight beam is isolated, as the transmitting light beam, to theP-polarized light beam and S-polarized light beam by the polarized beamsplitter 8, and the P-polarized light beam is rotated by 90 degrees inthe polarizing direction by a λ/2 phase difference plate 9 arranged atthe light emitting side surface of the polarized beam splitter 8 tobecome the S-polarized light beam and is then incident to a condenserlens 10. Moreover, the S-polarized light beam repeats reflection and isthen emitted from the light emitting surface of the neighboringpolarized beam splitter 8 and then enters the condenser lens 10. Thecondenser lens 10 is formed of at least one or more sheet of lens havingthe positive index of refraction and has a function to further condensethe S-polarized light beam. The light beam having passed the condenserlens 10 irradiates the liquid crystal display element 2. At the incidentside of this liquid crystal display element 2, an incident lightpolarizing plate 11 transmitting the S-polarized light beam is arranged.

[0028] In the projection type liquid crystal display apparatus of therelated art, the polarized light beam of only one direction istransmitted through combination of the incident light polarizing plate11, liquid crystal display element 2 and light emitting side polarizingplate 12 and thereby amount of light to be transmitted has been reducedto almost a half. However, since the polarized light beam splitter 8 isused in the preferred embodiment, the polarizing directions of therandomly polarized light beams emitted from the light source 1 areequalized in one polarizing direction and this light beam is then inputto the liquid crystal display element 2. Ideally, the brightness twotimes that of the projection type liquid crystal display apparatus ofthe related art can be attained.

[0029] Moreover, in this embodiment, the first array lens 6 and secondarray lens 7 of the present invention are same in the type thereof andlateral size of one lens cell has the ratio of almost 1/5.3 against thelateral size of the liquid crystal display element. For example, whenthe diagonal size of rectangular image display means of the liquidcrystal display element 2 is 0.9 inch, the diagonal size of rectangularshape of one lens cell is almost 0.17 inch, the total number of lenscells forming the first array lens 6 and second array lens 7 is 240 ormore and the focal distance of one lens cell is 30 mm or less, therebyrealizing reduction in size of optical system. Moreover, individualimages of almost 240 or more cells are overlapped on the liquid crystaldisplay element 2 to obtain more uniform image quality than that of theapparatus of related art. In addition, since the cell size is 0.17 inch,even when the shadow of electrode wire 28 crosses the cell, imagequality may be equalized because the number of cells is 240 or larger(almost 16×15 cells). Accordingly, the projection type liquid crystaldisplay apparatus can realize simultaneously size reduction of theapparatus as a whole and improvement of brightness.

[0030] Furthermore, the present invention provides the effect that theunwanted light beam is cut by the polarized beam splitter 8 formed byadding the light shielding plate 11 to the optical axis incident surfaceof the reflection prism of the S-polarized light beam located at thecenter of the pitch of the optical axis of the first array lens 6 and/orsecond array lens 7, namely at the surface in the side of the firstarray lens 6 and/or second array lens 7 and when unwanted light beam isabsorbed and cut by the incident light polarizing plate 11, heatradiation occurring when the light beam is converted to heat throughenergy conversion can be prevented. Moreover, color irregularitygenerated when unwanted light beam enters the liquid crystal displayelement 2 can also be reduced.

[0031] Moreover, the polarized beam splitter 8 of the present invention8 is formed thinner in the optical axis direction then the second arraylens 7 to realize shortening of the total length of optical system,light weight of the optical unit and increase of F value of the lightingsystem. Thereby, since small size and light weight can be realized andmoreover F value of the projecting lens 3 can also be increased inconnection with the lighting system, the projecting-lens 3 can also bereduced in size and weight.

[0032] The light beam having passed the liquid crystal display element 2reaches the display screen 4 passing the projecting means 3 such as, forexample, a zoom lens. An image formed on the liquid crystal displayelement 2 by the projecting means 3 is projected on the screen as theenlarged image by the function of the display apparatus.

[0033] Next, a practical embodiment of the present invention will beexplained.

[0034]FIG. 2 is a schematic diagram illustrating the structure of theprojection type liquid crystal display apparatus of the presentinvention. The embodiment of FIG. 2 is a 3-plate type projection displayapparatus using three transmitting type liquid crystal display elements2 as the liquid crystal light bulbs corresponding to so-called threeprimary colors of R(Red), G(Green) and B(Blue). In this embodiment, thelight beam emitted from the lamp 13 such as, for example, super-highpressure mercury lamp as the light source is once reflected by aparabolic reflection mirror type reflector 5 and is thereafter incidentto the first array lens 6 which is formed by a plurality of condenserlenses provided at the rectangular frame almost in the same size as thelight emitting aperture of such parabolic reflection mirror typereflector 5 to condense the light emitted from the lamp unit 14 and forma plurality of secondary light source images and then passes the secondarray lens 7 which is formed by a plurality of condenser lenses andlocated at the area near a plurality of secondary light source images tofocus individual lens images of the first array lens 5 to the liquidcrystal display element 2. This light beam emitted from the second arraylens 7 is incident to a line of rhombus prisms almost in the ½ size ofwidth of each lens arranged in such a manner as fitting to the pitch inthe lateral direction of the optical axis of lens of the second arraylens 7. A film of the polarized beam splitter 8 is formed on the surfaceof this prism and therefore the incident light beam is isolated to theP-polarized light beam and S-polarized light beam by the polarized beamsplitter 8. The P-polarized light beam travels in straight in thepolarized beam splitter 8, it is then rotated by 90 degrees in thepolarizing direction by the λ/2 phase difference plate 9 provided at thelight emitting surface of the prism and is then emitted after it isconverted to the S-polarized light beam. Meanwhile, the S-polarizedlight beam is reflected by the polarized beam splitter 8, it is thenreflected again in the intrinsic optical axis direction within theneighboring rhombus prism and it is emitted as the S-polarized lightbeam. Of course, the polarized beam splitter 8 of the present inventionadds a light shielding member 27 (see FIG. 4A and FIG. 4B) to theoptical axis incident surface of the reflection prism of the S-polarizedlight beam located at the center of the pitch of the optical axis ofeach lens of the second array lens 7, namely to the surface in the sideof the second array lens 7. Thereafter, light beam is condensed to theliquid crystal display element 2 by the condenser lens 10. In the courseof this process, the light beam emitted from the polarized beam splitter8 is bent in its optical path by 90 degrees with a total reflectionmirror 15 and a B(Blue), G(Green) reflection dichroic mirror 16 allowsthe R (Red) color light beam to pass and reflects the B, G lights. The Rlight beam having passed the dichroic mirror is bent in its optical pathby 90 degrees with the total reflection mirror 17 for R light beam,passes through the condenser lens 18 and incident polarizing plate 11provided before the liquid crystal display element, is incident to theliquid crystal display element 2 formed of an opposing electrode andliquid crystal or the like and then passes through the polarizing plate12 provided in the light emitting side of the liquid crystal displayelement 2.

[0035] The liquid crystal display element 2 is provided with the liquidcrystal display areas in such number (for example, 800 pixels in lateraldirection×600 pixels in vertical direction for each color of threecolors) corresponding to the display pixels. Depending on the signaldriven from the external side, polarizing angle of each pixel of theliquid crystal display element 2 changes and finally the light in thedirection matched with the polarizing direction of the polarizing plate12 is emitted and the light in the orthogonal direction is absorbed bythe polarizing plate 12. The light polarized by the intermediate angledetermines amount of light beam passing through the polarizing plate andamount of light beam absorbed by the polarizing plate in relation to thepolarizing angle of the polarizing plate 12. As explained above, animage is projected conforming to the external input signal.

[0036] The R light beam emitted from the polarizing plate 12 isreflected by the dichroic prism 19 having the function to reflect the Rlight beam, then enters the projecting means 3 such as a zoom lens andis then projected to the display screen.

[0037] On the other hand, the B light beam and G light beam havingpassed the B, G transmitting dichroic prism 19 enter a G-reflectiondichroic mirror 20. This mirror 20 reflects the G light beam. Thereflected G light beam then passes through the condenser lens 18 andincident polarizing plate 11 provided before the liquid crystal displayelement 2 and then enters the liquid crystal display element 2 andpasses through the polarizing plate 12 provided in the light emittingside of the liquid crystal display element 2. The G light beam emittedfrom the polarizing plate 12 passes through the dichroic prism 19 havingthe function to transmit the G light beam, enters the projection lens 3and is then projected to the display screen.

[0038] Meanwhile, the B light beam transmitted through the G reflectiondichroic mirror 20 passes through a relay lens 21, it is then bend inthe optical path by 90 degrees with a total reflection mirror 22 to passthrough the relay lens 21, thereafter it is then bent again in itsoptical path by 90 degrees with a total reflection mirror 23 to passthrough the condenser lens 18 and incident polarizing plate 11 providedbefore the liquid crystal display element, it enters the liquid crystaldisplay element 2 and finally passes through the polarizing plate 12provided in the light emitting side of the liquid crystal displayelement. The B light beam emitted from the polarizing plate 12 isreflected by the dichroic prism 19 having the function to reflect the Blight beam and thereafter enters the projection lens 3 for projection tothe display screen.

[0039] Moreover, the B light beam transmitted through the G reflectiondichroic mirror 20 passes through the relay lens 21, it is then bent inits optical path by 90 degrees with the total reflection mirror 22 topass the relay lens 21, thereafter it is bent again in its optical pathby 90 degrees with the total reflection mirror 23 to pass the condenserlens 18 and incident polarizing plate 11 provided before the liquidcrystal display element, it enters the liquid crystal display element 11to pass through the polarizing plate 12 provided in the light emittingside of the liquid crystal display element 2. The B light beam emittedfrom the polarizing plate 12 is reflected by the dichroic prism 19having the function to reflect the B light beam and enters theprojection lens 3 for projection to the display screen.

[0040] As explained above, the light beams respectively corresponding toR, G, B are isolated and combined by the color isolating means and colorcombining means and the images of respective colors are combined on thescreen to attain the enlarged image by enlarging the image on the liquiddisplay element respectively corresponding to R, G, B with theprojection lens 3. In the same figure, the power supply circuit 24 andimage signal circuit 25 are arranged as illustrated in the figure andheat generated by the light source 1 is guided to the external side witha blowing fan 26. Moreover, in this embodiment, the light beams emittedrandomly from the light source are aligned in one direction andtherefore less amount of heat is generated from the incident polarizingplate.

[0041] Moreover, the light source and projecting means are arrange insuch a manner that the optical axes thereof are orthogonal with eachother and in addition, the apparatus as a whole can be reduced in sizeby arranging the power supply circuit 24 and image signal circuit 25 asillustrated in the figure via the color isolating and combining unitconsisting of the color isolating means and liquid crystal displayelement and color combining means.

[0042] In addition, in this embodiment, the first array lens 6 and thesecond array lens 7 used in the present invention are formed in the sameshape, the lateral size of one lens cell has a ratio of about 1/5.3 ofthe lateral size of the liquid crystal display element 2. For instance,when the diagonal size of rectangular shape of the image display area ofthe liquid crystal display element 2 is 0.9 inch, the diagonal size ofrectangular shape of one lens cell of the fist array lens 6 and secondarray lens 7 is about 0.17 inch, the diagonal size of rectangular shapeof one lens cell of the first array lens 6 and second array lens 7 isabout 0.17 inch, the total number of lens cells forming the first arraylens 6 and second array lens 7 is about 240 or more and the focaldistance of one lens cell of the first array lens 6 and second arraylens 7 is 30 mm or less. As a result, size reduction of the opticalsystem can be attained. Moreover, individual images of almost 240 ormore cells are overlapped on the liquid crystal display element 2 andthereby more homogeneous image than that of the apparatus of related artcan be obtained.

[0043] In addition, even if the shadow of the electrode wire 28 iscrossing the cell because the cell size is 0.17 inch, when the number ofcells exceeds about 240 cells (almost 15×15 cells), image quality can bemore equalized. Therefore, size reduction and improvement of brightnessof the apparatus as a whole can be realized simultaneously in theprojection type liquid crystal display apparatus.

[0044] Moreover, when it is required to improve brightness andhomogeneity of image using the liquid crystal display element withmicro-lens or the like, the F value of the lighting system must be setto about 2 to 3. Even in this case, an interval of the first array lensand second array lens of the present invention can be reduced to thedistance of 30 mm or less and as a result the size reduction of opticalsystem can be realized.

[0045] Furthermore, in the present invention, since a polarizing andcombining means (in some cases, a light shielding member is added) iscombined and the polarized beam splitter 8 as the polarizing andcombining means is formed thinner than the second array lens 7 (namely,the polarizing beam splitter 8 is set to 2 mm or less when the secondarray lens 7 is about 2.5±0.5 mm), length of optical path can beshortened and the total reflection mirror 15 can be arranged closely,thereby resulting in size reduction of the set.

[0046] In the embodiment of the present invention illustrated in FIG. 2,the lighting and optical system comprises a lamp unit 14, a first arraylens 6, a second array lens 7, a polarized beam splitter 8, a λ/2 phasedifference plate 9, a condenser lens 10 and a total reflection mirror 15and establishes the optical path until the part for isolating the lightbeam emitted from the lamp 13 to the R, G, B light beams. Moreover, theoptical unit includes the lighting and optical system to define theprocess up to the isolation of the light beam emitted from the lightingand optical system to the R, G, B light beams respectively using the B(Blue), G(Green) reflection dichroic mirror 16 and G reflection dichroicmirror 20 or the like and also to define the optical path up to theprojecting means 3 via the dichroic prism 19 which allows application ofthe isolated R, G, B light beams to the respective liquid crystaldisplay element 2, reflects the R light beam and B light beam andtransmits the G light beam.

[0047]FIG. 3 is a diagram illustrating a part of effect of the firstembodiment of the present invention.

[0048]FIG. 3 illustrates the lighting and optical system of theprojection type liquid crystal display apparatus. The light source 1 hasa circular reflecting mirror 5 and an electrode wire 28 having thediameter of almost 0.6 mm or less provided at the single side of thelamp electrode within the reflecting mirror 5.

[0049] The light beam radiated from a bulb of the light source 1 iscondensed by an elliptical surface or parabolic surface or non-sphericalsurface reflector 5 and is then incident to the first array lens 6.After passing the first array lens 6, the light beam passes the secondarray lens 7 and then enters the polarized beam splitter 8. Thetransmitted light of this incident light beam is isolated to theP-polarized light beam, while the reflected light thereof is isolated tothe S-polarized light beam respectively by the polarized beam splitter8. The P-polarized light beam is rotated by 90 degrees in its polarizingdirection by the λ/2 phase difference plate 9 provided at the lightemitting side surface of the polarized beam splitter 8 to become theS-polarized light beam and enters the condenser lens 10. Moreover, theS-polarized light beam is repeatedly reflected and is then emitted fromthe light emitting surface of the neighboring polarized beam splitter 8to enter the condenser lens 10. The condenser lens 10 is formed of atleast a sheet of lens or more lenses having the positive index ofrefraction having the function to further condense the S-polarized lightbeam. The light beam having passed the condenser lens 10 irradiates theliquid crystal display element 2.

[0050] Referring to FIG. 3, the first array lens 6 and second array lens7 of the present invention are formed in the same shape. The lateralsize of one lens cell has a ratio of almost 1/5.3 of the lateral size ofthe liquid crystal display element 2. For example, when the diagonalsize of rectangular shape of the image display area of the liquidcrystal display element 2 is 0.9 inch, the diagonal size of rectangularshape of one lens cell of the first array lens 6 and second array lens 7is almost equal to the size of 0.17 inch, the total number of lens cellsforming the first array lens 6 and second array lens 7 is 240 or moreand the lens focal length of one lens cell of the first array lens 6 andsecond lens array 7 (FIG. 3 is a schematic diagram) is 30 mm or less.Accordingly, size reduction of optical system can be attained. Moreover,as indicated by dotted line of FIG. 3, individual images of 240 cells ormore are overlapped on the liquid crystal display element 2 and morehomogeneous image quality than that of the related art can be obtained.In addition, since the cell size is 0.17 inch, even if the shadow of theelectrode wire 28 crosses the cell, when the number of cells is about240 (almost 16×15 cells) or more, seven (7) to eight (8) lines arearranged in the single side. When the cell size is 0.17 inch, six linesof belt type shadow having the width of almost 0.6 mm are arranged inone cell size. Therefore, when at least six lines are arranged in thesingle side of cell, dark area resulting from shadow of the electrodewire 28 on the liquid crystal display element can be freed and resultantcolor irregularity can also be eliminated and homogeneous image qualitycan be attained. In this case, since the electrode wire exists in thesingle side of the right and left sides of the optical axis center, whenone to two lines are provided as the allowance of the vertical orhorizontal arrangement of array lens, 14 to 16 lines in minimum arerequired. Accordingly, when the number of cells is about 240 or more,shadow of the electrode wire of almost 0.6 mm or less is reflectedequally like the diagonal line of the figure on the liquid crystaldisplay element. Thereby, image quality assuring equal brightness and nocolor irregularity can be attained.

[0051] Therefore, the projection type liquid crystal display apparatuscan simultaneously realize reduction in size and improvement inbrightness of the apparatus as a whole. Moreover, since the first arraylens 6 and second array lens 7 are formed in the same shape, only onetype is used and cost reduction can also be attained.

[0052]FIG. 4 is a diagram illustrating the second embodiment of thepresent invention.

[0053] The polarized beam splitter 8 illustrated in FIG. 4A and FIG. 4Bis provided with a polarized beam splitter film at the glass platethereof for isolating the P-polarized light beam and S-polarized lightbeam. After this film is laminated using a bonding agent, the glassplate is sliced in the angle of 45 degrees. Therefore, as illustrated inFIG. 4, there is provided a flat plate structure wherein a plurality oflongitudinally elongated rhombus prisms are arranged. Such filming maybe attained by conducting the mirror evaporation of aluminum or silveror the like in every other surface. However, since this mirror sectionhas a role of reflecting the S-polarized light beam, it is required toprovide a certain means for not allowing the light beam to enter thelight path of the prism.

[0054] Therefore, the polarized beam splitter 8 of the present inventionadds a light shielding member 27 to the optical axis incident surface ofthe S-polarized light beam reflection prism located at the center of thepitch of the optical axis of each lens of the second array leans 7,namely to the surface in the side of the second array lens 7 to providethe effect that unwanted light beams can be cut and when the light beamis absorbed and cut by the incident polarizing plate 11, the heatgenerated through energy conversion from the light beam to heat energycan be prevented. This light shielding member 27 is formed of slit typereflection films, or ground glass type dispersion films, or metal sealfor light shieldings, or heat-proof seals, or slitted metal plates, ormetal plating, or the like in every other one formed with silver oraluminum evaporation film.

[0055] In the flat plate structure where a plurality of polarized beamsplitters 8 are arranged as explained above, they are bonded in everyother line, it is also possible that the isolated P-polarized light beamis converted to the S-polarized light beam, the light beam emitted fromthe polarized beam splitter 8 is totally set to the S-polarized lightbeam, or after the isolated S-polarized light beam is emitted byreflection from the prism adjacent to the incident prism, the light beamemitted from the polarized beam splitter 8 is totally set to theP-polarized light beam with the λ/2 phase difference plates 9.

[0056] When a plurality of rhombus prisms of the flat type polarizedbeam splitter 8 explained above are arranged conforming to the pitch, inthe lateral arrangement direction, of the lens optical axis of thesecond array lens 7 and one polarized beam splitter 8 and the otherpolarized beam splitter 8 are bonded symmetrically in the right and leftsides of the center under the condition rotated each other by 180degrees in such a manner that the second array lens 7 is dividedrespectively to half areas in the right and left or upper and lowersections keeping a clearance, for example, h equal to ½ of the width ofthe optical axis pitch at the center of the second array lens 7, thelight shielding member 27 provided in the second array lens 7 can bematched in higher accuracy with the pitch in the lateral arrangementdirection of the polarized beam splitter 8 and thereby highly accuratebonding among the second array lens 7, light shielding member 27 andpolarized beam splitter 8 which has been considered difficult inmanufacturing process can be realized.

[0057] In the structure of the related art, since the light transmittingefficiency is lowered even when interface is formed of reflection-prooffilm in such a case that the flat type polarized beam splitter 8 formedsymmetrically in the right and left direction as illustrated in FIG. 4Aor FIG. 4B and interface between optical parts such as this polarizedbeam splitter 8 and second array lens 7 is formed of the layer of air,this polarized beam splitter 8 and the second array lens 7 are bondedconforming to the pitch in the lateral arrangement direction of the lensoptical axis and the polarized beam splitter 8. In this case, the slittype light shielding plate to cut the unwanted light beam is arrangedbefore the second array lens 7, namely in the side of light source inview of shielding the unwanted light element, namely the hatched elementin the FIG. 4B before the light beam enters the polarized beam splitter8. However, in this case, the light shielding member 27 is formed of amember such as metal plate having a slit and therefore it must besupported independent of the optical axis.

[0058] For this reason, the required light beam also has been shieldeddue to part accuracy error or assembling accuracy error of the lightshielding member 27 and the number of parts has also been increased evenin the case of assembling, resulting in increase of processing cost.

[0059] However, in the present invention, since the polarized beamsplitter 8 is bonded symmetrically in the right and left direction inboth sides of the center to the second array lens 7 providing the lightshielding member 27 and the light shielding member 27 is formed of anevaporation film or the like, the light incident surface of the prism inthe S light path can be shielded almost without any error and the numberof parts can also be reduced to improve the assembling efficiency.

[0060] Moreover, in the present invention, the process of the secondstage that the flat type polarized beam splitter 8 which is symmetricalin the right and left direction is produced by a maker and is thenbonded to the second array lens 7 like the prior art is eliminated but acouple of polarized beam splitters 8 are bonded to the second array lens7 in the process of the first stage. As a result, processing cost can belowered.

[0061] In addition, since the polarized beam splitter 8 of the relatedart is integrated in the right and left sides, the bonding accuracy isoverlapped from the left end to the right end and therefore when thebeam splitter 8 is bonded to the second array lens 7, it is shared atthe center to the right and left side, certainly resulting in thebonding accuracy error in the right and left sides, for example, theerror of ±0.25 in both right and left sides.

[0062] However, in the present invention, since the polarized beamsplitter 8 is bonded to the second array lens 7 providing individuallight shielding members 27 in the right and left sides, the accuracyerror from the center is never accumulated and therefore since the leftpolarized beam splitter 8 can define the left center thereof or the lensoptical axis of the left half on the second array lens 7 in a largeamount of light beam as the center for accuracy sharing, the accuracyerror can be controlled to ±0.125 in the numerical value. When the rightside polarized beam splitter 8 is bonded to the second array lens 7 inthe same manner, the effect to reduce the bonding accuracy error canalso be attained as in the case of the left side. Thereby, positionaldisplacement of the optical axis due to the bonding error of thepolarized beam splitter 8 in the half width of the lens optical axispitch of the second array lens 7 can be reduced and amount of incidentlight beam from the second array lens 7 to be reflected by the polarizedbeam splitter 8 can also be reduced. Accordingly, the light transmittingefficiency can be improved to realize improvement in brightness. Thepolarized beam splitter 8 is naturally formed thinner than the first orsecond array lens 7 and when it is required to shield the light beamwith an evaporation film, the evaporation system is different from thatwhen the polarized beam splitter 8 formed thicker than the ordinarysecond array lens 7 is used. Namely, it is necessary for not cutting thelight beam to be used to set the area of the light shielding means torealize light shielding for rather narrower area by considering thebonding accuracy error rather than the P-polarized light beam apertureor S-polarized light beam aperture of the polarized beam splitter 8 forlight shielding.

[0063] Such accuracy of light shielding means, for example, an idea formaking the width of light shielding film a little smaller than the pitchwidth of the polarized beam splitter 8 is effective for improvement oflight efficiency when a larger number of cells are used for thepolarized beam splitter 8 which is thinner than the second lens array 7and the second lens array 7. Moreover, in some cases, it is alsoeffective that many reference positions are prepared and the polarizedbeam splitter 8 is divided for the bonding as will be explained laterconsidering the bonding accuracy.

[0064]FIG. 5 is a diagram illustrating the external view of the thirdembodiment of the present invention. In the present invention, the firstarray lens 6 or second lens array 7 is provided with a first positioningsection 27 as the positioning reference of each lens and the polarizedbeam splitter 8 is also provided a second positioning section 28 as thepositioning reference. This first positioning section 27 and the secondpositioning section 28 are respectively formed by the engraving(illustrated in FIG. 5), recessed area, projected area, end surface,cutout area, stepped area or marking or the like and the absolutepositioning of the first array lens 6 or second array lens 7 can beperformed by aligning the first positioning section 27 to thepositioning area (not illustrated) provided to the structure member forsupporting and fixing the first array lens 6 or second array lens 7. Inthe same manner, the absolute positioning of the polarized beam splitter8 can also be performed by aligning the second positioning section 28 ofthe polarized beam splitter 8 to the positioning area (not illustrated)provided to the structure member for supporting and fixing the polarizedbeam splitter 8.

[0065] According to the present invention, respective referencepositioning can be made easily when assembling the first array lens 6,second array lens 7 and polarized beam splitter 8 to the optical partsupporting structure member and relative lens optical axes of the firstarray lens 6 and array lens 7 may be matched at the design position andarrangement of polarized beam splitter 8 can be located at the positionresulting in the maximum light application efficiency conforming to thelateral arrangement pitch of the lens optical axis explained above.Thereby, optical performance can be improved and the assembling work ofthese optical parts can be simplified to improve the working efficiency.

[0066] In addition, as illustrated in FIG. 5, the polarized beamsplitter 8 can be arranged to the optimum position for each lens opticalaxis of the second array lens 7 by providing the first positioningsection 27 of the second array lens 7 and the second positioning section28 of the polarized beam splitter 8 to the positions to be matched andthen matching these positioning sections at the time of assembling.Thereby, matching can be made to the position providing the maximumlight application efficiency in view of improving the opticalperformance.

[0067]FIG. 6 is a diagram illustrating the external appearance of thefourth embodiment of the present invention. In the present invention,the first array lens 6 or second array lens 7 is provided with the firstpositioning section 27 as the positioning reference of each leans andthe polarized beam splitter 8 is provided with the second positioningsection 28 as the positioning reference. These first positioning section27 and second positioning section 28 are formed as the recessed area andprojected area as illustrated in FIG. 6A. These first and secondpositioning sections 27, 28 are combined to match the projected area andrecessed area for the positioning so that the polarized beam splitter 8is located at the optimum position for the lens optical axis of eachlens of the first array lens 6 or second array lens 7 and thereafter thepolarized beam splitter 8 can be bonded to the first array lens 6 or thesecond array lens 7. Accordingly, matching can be made to the positionproviding the maximum application efficiency of the light and bondingexplained above assures reduction in amount of light reflected at theinterface of the optical elements and improvement in the opticalperformance.

[0068] In addition, the first positioning section 27 and secondpositioning section 28 are not limited to the recessed area andprojected area and these may be FIG. 6B in which end faces of each partare positioned so as to coincidence with optical axes as illustrated, orFIG. 6C the first positioning section 27 is positioned in the secondpositioning section 28 as illustrated, or FIG. 6D the type where entirepart of one positioning frame is engaged with the other frame asillustrated, or FIG. 6E the type where both sections are positioned andbonded via a third member such as the positioning jig 31 or the like asillustrated. Moreover, it is also possible to improve accuracy bydesigning the sizes, considering the accumulated element accuracy error,so that the polarized beam splitter 8 is located to the optimum positionfor each lens optical axis of the array lens.

[0069] According to the present invention, length of optical path can beshortened and the apparatus can be reduced in size. Brightness can alsobe improved. Moreover, image quality improvement such as equalization ofimage quality can also be realized. In addition, generation of heat dueto unwanted light beam can also be prevented.

[0070] The present invention allows any modification of the embodimentexplained above without departing from the spirit and scope of theprincipal characteristics thereof. The embodiment explained above istherefore only an example of the present invention and should not belimited thereto. The scope of the present invention is limited only bythe appended claims. Moreover, any modifications and changes in regardto the appended claims should be within the scope of the presentinvention.

What is claimed is:
 1. Imaging apparatus to form an optical imagedepending on a video signal by irradiating the display elements with thelight beam from a lighting optical system, said lighting optical systemcomprising an array lens in which the lens to condense the light beamfrom a light source unit to form a plurality of light source images isused and any one of the diagonal size, vertical size, lateral size oflens cell is almost 1/(4.5 or more) for each corresponding size of saiddisplay elements.
 2. Imaging apparatus to form an optical imagedepending on a video signal by irradiating the display elements with thelight beam from a lighting optical system, said lighting optical systemcomprising an array lens in which a lens to condense the light beam froma light source unit to form a plurality of light source images is usedand the diagonal size of lens cell is set to almost 0.18 inch or less.3. Imaging apparatus according to claim 2 , wherein said light sourceunit includes an electrode wire having the thickness of 0.6 mm or lessin the single side of lamp electrode.
 4. Imaging apparatus to form anoptical image depending on a video signal by irradiating the displayelements with the light from the lighting optical system, said lightingoptical system comprising a lens array in which a lens to condense thelight from the light source unit to form a plurality of light sourceimages and the total number of lens cells is set to almost 240 or more.5. Imaging apparatus according to claim 4 , wherein said light sourceunit includes an electrode wire having the thickness of 0.6 mm or lessin the single side of lamp electrode.
 6. Imaging apparatus to form anoptical image depending on a video signal by irradiating the displayelements with the light from the lighting optical system, said lightingoptical system comprising an array lens in which a lens to condense thelight from the light source unit to form a plurality of light sourceimages and lens focal distance of lens cell is set to almost 30 mm orless.
 7. Imaging apparatus to form an optical image depending on a videosignal by irradiating the display elements with the light from thelighting optical system, said lighting optical system comprising anarray lens having the structure that a lens to condense the light fromthe light source unit to form a plurality of light source images is usedand any one of diagonal size, vertical size, lateral size of lens cellis set almost to 1/(4.5 or more) for each corresponding size of saiddisplay elements and a processing section for isolating the light fromsaid light source unit or array lens to the P-polarized light beam andS-polarized light beam with an isolating means and then changing thepolarizing direction of any one of said both P- and S-polarized lightbeams with a converting means, whereby the center axis of arrangement ofsaid isolating means is matched with the pitch in any one of verticaland lateral arrangement directions of the lens optical axis of at leastsaid array lens.
 8. Imaging apparatus to form an optical image dependingon a video signal by irradiating the display elements with light fromthe lighting optical system, said lighting optical system comprising anarray lens having the structure that a lens to condense the light fromthe light source unit to form a plurality of light source images is usedand the diagonal size of lens cell is set to almost 0.18 inch or lessand a processing section for isolating the light beam from said lightsource unit or said array lens to the P-polarized light beam andS-polarized light beam with an isolating means and converting thepolarizing direction of any one of both polarized light beams with aconverting means, whereby the center axis of arrangement of saidisolating means is matched with the pitch of any direction of thevertical and lateral arrangement directions of the lens optical axis ofat least said array lens.
 9. Imaging apparatus to form an optical imagedepending on a video signal by irradiating the display elements with thelight from the lighting optical system, said lighting optical systemcomprising an array lens having the structure that a lens to condensethe light from the light source unit to form a plurality of light sourceimages is used and the total number of lens cells is set to almost 240or more and a processing section for isolating the light from said lightsource unit or said array lens to the P-polarized light beam andS-polarized light source with an isolating means and converting thepolarizing direction of any one of said both polarized light beams witha converting means, whereby the center axis of arrangement of saidisolating means is matched with the pitch in any direction of thevertical and lateral arrangement directions of lens optical axis of atleast said array lens.
 10. Imaging apparatus to form an optical imagedepending on a video signal by irradiating the display elements with thelight from the lighting optical system, said lighting optical systemcomprising an array lens having the structure that a lens to condensethe light from the light source unit to form a plurality of light sourceimages is used and a lens focal distance of lens cell is set to almost30 mm or less and a processing section for isolating the light from saidlight source unit or said array lens to the P-polarized light beam andS-polarized light beam with an isolating means and converting thepolarizing direction of any one of both polarized light beams with aconverting means, whereby the center axis of arrangement of saidisolating means is matched with the pitch in any arrangement directionof the vertical and lateral directions of lens optical axis of at leastsaid array lens.
 11. Imaging apparatus to form an optical imagedepending on a video signal by irradiating the display elements with thelight from the lighting optical system, said lighting optical systemcomprising an array lens having the structure that a lens to condensethe light from the light source unit to form a plurality of light sourceimages is used and any one of diagonal size, vertical size, lateral sizeof lens cell is set to almost 1/(4.5 or more) for each correspondingsize of said display elements, an isolating section for isolating thelight from said light source unit or array lens to the P-polarized lightbeam and S-polarized light beam, a light shielding section located inthe light incident side rather than said isolating section to eliminateunwanted light beam and a converting section for converting thepolarizing direction of any one of the P-polarized light beam andS-polarized light beam of the light emitted from said isolating section,whereby the renter axis of arrangement of said isolating section ismatched with the pitch in any arrangement direction of vertical andlateral directions of lens optical axis of at least said array lens. 12.Imaging apparatus to form an optical image depending on a video signalby irradiating the display elements with the light from the lightingoptical system, said lighting optical system comprising an array lenshaving the structure that a lens to condense the light from the lightsource unit to form a plurality of light source images is used and thediagonal size of lens cell is set to almost 0.18 inch or less, anisolating section for isolating the light from said light source unit orarray lens to the P-polarized light beam and S-polarized light beam, alight shielding section located in the light incident side rather thansaid isolating section to eliminate unwanted light beam and a convertingsection for converting the polarizing direction of any one of theP-polarized light beam and S-polarized light beam of the light emittedfrom said isolating section, whereby the center axis of arrangement ofsaid isolating section is matched with the pitch in any arrangementdirection of the vertical and lateral directions of the lens opticalaxis of at least said array lens.
 13. Imaging apparatus to form anoptical image depending on a video signal by irradiating the displayelements with the light from the lighting optical system, said lightingoptical system comprising an array lens having the structure that a lensto condense the light from the light source unit to form a plurality oflight source images is used and the total number of lens cells is set toalmost 240 or more, an isolating section for isolating the light fromsaid light source unit or array lens to the P-polarized light beam andS-polarized light beam, an light shielding section located at the lightincident side rather than said isolating section to eliminate unwantedlight beam and a converting section for converting the polarizingdirection of any one of the P-polarized light beam and S-polarized lightbeam of the light emitted from said isolating section, whereby thecenter axis of the arrangement of said isolating section is matched withthe pitch in any arrangement direction of vertical and lateraldirections of the lens optical axis of at least said array lens. 14.Imaging apparatus to form an optical image depending on a video signalby irradiating the display elements with the light from the lightingoptical system, said lighting optical system comprising an array lenshaving the structure that a lens to condense the light from the lightsource unit to form a plurality of optical source images is used and alens focal distance of lens cell is set to almost 30 mm or less, anisolating section for isolating the light from said light source unit orarray lens to the P-polarized light beam and S-polarized light beam, alight shielding section located in the light incident side rather thansaid isolating section to remove unwanted light beam and a convertingsection for converting the polarizing direction of any one of theP-polarized light beam and S-polarized light beam of the light emittedfrom said isolating section, whereby the center axis of arrangement ofsaid isolating section is matched with the pitch in any arrangementdirection of the vertical and lateral directions of the lens opticalaxis of at least said array lens.
 15. Imaging apparatus to form anoptical image depending on a video signal by irradiating the displayelements with the light from the lighting optical system, said lightingoptical system comprising an array lens having the structure that afirst array lens to condense the light from the light source unit toform a plurality of secondary order light source images and a secondarray lens to focus a lens image of said first array lens to saiddisplay elements are used and at least any one of the diagonal size,vertical size and lateral size of any one or both lens cells of saidfirst and second array lenses is set to almost 1/(4.5 or more) for eachcorresponding size of said display elements, an isolating section forisolating the light from said light source unit or array lens to theP-polarized light beam and S-polarized light beam and a convertingsection for converting the polarizing direction of any one of theP-polarized light beam and S-polarized light beam of the light emittedfrom said isolating section, whereby at least said first, second arraylenses, said isolating section and said converting section are arrangedin the manner that respective optical axes thereof are almost matchedwith a line.
 16. Imaging apparatus according to claim 15 , wherein saidisolating section is a polarized beam splitter and said convertingsection is a λ/2 phase difference plate.
 17. Imaging apparatus to forman optical image depending on a video signal by irradiating the displayelements with the light from the lighting optical system, said lightingoptical system comprising an array lens having the structure that afirst array lens to condense the light from the light source unit toform a plurality of secondary order light source images and a secondarray lens to focus a lens image of said first array lens to saiddisplay elements are used and the diagonal size of the lens cell of anyone or both first and second array lenses is set to almost 0.18 inch orless, a isolating section for isolating the light from said light sourceunit or array lens to the P-polarized light beam and S-polarized lightbeam and a converting section for converting the polarizing direction ofany P-polarized light beam and S-polarized light beam of the lightemitted from said isolating section, whereby at least said first andsecond array lenses, said isolating section and said converting sectionare arranged in the manner that the respective optical axes thereof arealmost matched with a line.
 18. Imaging apparatus according to claim 17, wherein said isolating section is a polarized beam splitter and saidconverting section is a λ/2 phase difference plate.
 19. Imagingapparatus to form an optical image depending on a video signal byirradiating the display elements with the light from the lightingoptical system, said lighting optical system comprising an array lenshaving the structure that a first array lens to condense the light fromthe light source unit to form a plurality of secondary order lightsource images and a second array lens to focus a lens image of saidfirst array lens to said display elements are used and the total numberof any one or both lens cells of said first and second array lenses isset to almost 240 or more, an isolating section for isolating the lightfrom said light source unit or array lens to the P-polarized light beamand S-polarized light beam and a converting section for converting thepolarizing direction of any one of the P-polarized light beam andS-polarized light beam of the light emitted from said isolating section,whereby at least said first and second array lenses, said isolatingsection and said converting section are arranged in the manner that therespective optical axes thereof are almost matched with a line. 20.Imaging apparatus according to claim 19 , wherein said isolating sectionis a polarized beam splitter and said converting section is a λ/2 phasedifference plate.
 21. Imaging apparatus to form an optical imagedepending on a video signal by irradiating the display elements with thelight from the lighting optical system, said lighting optical systemcomprising an array lens having the structure that a first array lens tocondense the light from the light source unit to form a plurality ofsecondary order light source images and a second array lens to focus alens image of said first array lens to said display elements are usedand the lens focal distance of lens cell of said first and second arraylenses is set to almost 30 mm or less, an isolating section forisolating the light from said light source unit or array lens to theP-polarized light beam and S-polarized light beam and a convertingsection for converting the polarizing direction of any one of theP-polarized light beam and S-polarized light beam of the light emittedfrom said isolating section, whereby at least said first and secondarray lenses, said isolating section and said converting section arearranged in the manner that respective optical axes thereof are almostmatched with a line.
 22. Imaging apparatus according to claim 21 ,wherein said isolating section is a polarized beam splitter and saidconverting section is a λ/2 phase difference plate.
 23. Imagingapparatus to form an optical image depending on a video signal byirradiating the display elements with the light from the lightingoptical system, said lighting optical system comprising an array lenshaving the structure that a first array lens to condense the light fromthe light source unit to form a plurality of secondary order lightsource images and a second array lens to focus a lens image of saidfirst array lens to said display elements are used and at least any oneof the diagonal size, vertical size and lateral size of any one or bothlens cells of the first and second array lenses is set to almost 1/(4.5or more) for each corresponding size of said display elements, anisolating section for isolating the light from said light source unit orarray lens to the P-polarized light beam and S-polarized light beam anda converting section for converting the polarizing direction of any oneof the P-polarized light beam and S-polarized light beam of the lightemitted from said isolating section, whereby at least said array lens,said isolating section and said converting section are arranged in themanner that respective optical axes thereof are almost matched with aline and an external size of the apparatus as a whole is set to the A4file size or less.
 24. Imaging apparatus to form an optical imagedepending on a video signal by irradiating the display elements with thelight from the lighting optical system, said lighting optical systemcomprising an array lens having the structure that a first array lens tocondense the light from the light source unit to form a plurality ofsecondary order light source images and a second array lens to focus alens image of said first array lens to said display elements are usedand the lens focal distance of lens cell of said first and second arraylenses is set to almost 30 mm or less, an isolating section forisolating the light from said light source unit or array lens to theP-polarized light beam and S-polarized light beam and a convertingsection for converting the polarizing direction of any one of theP-polarized light beam and S-polarized light beam of the light emittedfrom said isolating section, whereby at least said first and secondarray lenses, said isolating section and said converting section arearranged in the manner that respective optical axes thereof are almostmatched with a line and an external size of the apparatus as a whole isset to the A4 file size or less.
 25. Optical unit to form an opticalimage depending on a video signal by irradiating the display elementswith the light from the lighting optical system, said lighting opticalsystem comprising an array lens having the structure that a lens tocondense the light from the light source unit to form a plurality oflight source images is used and at least any one of the diagonal size,vertical size and lateral size of the lens cell is set to almost 1/(4.5or more) for corresponding each size of said display elements. 26.Optical unit to form an optical image depending on a video signal byirradiating the display elements with the light from the lightingoptical system, said lighting optical system comprising an array lenshaving the structure that a lens to condense the light from the lightsource unit to form a plurality of light source images is used and aplurality of lens cells having the diagonal size of almost 0.18 inch orless are arranged within a plane.
 27. Optical unit to form an opticalimage depending on a video signal by irradiating the display elementswith the light from the lighting optical system, said lighting opticalsystem comprising an array lens having the structure that a lens tocondense the light from the light source unit to form a plurality oflight source images is used and the total number of lens cells arrangedin a plane is set to almost 240 or more.
 28. Optical unit to form anoptical image depending on a video signal by irradiating the displayelements with the light from the lighting optical system, said lightingoptical system comprising an array lens having the structure that a lensto condense the light from the light source unit to form a plurality oflight source images is used and a plurality of lens cells having thefocal distance of almost 30 mm or less are arranged in a plane. 29.Optical unit to form an optical image depending on a video signal byirradiating the display elements with the light from the lightingoptical system, said lighting optical system comprising an array lenshaving the structure that a fist array lens to condense the light fromthe light source unit to form a plurality of secondary order lightsource images and a second array lens to focus a lens image of saidfirst array lens to said display elements are used and at least any oneof the diagonal size, vertical size and lateral size of any one or bothlens cells of the first and second array lenses is set to almost 1/(4.5or more) for each corresponding size of said display elements, anisolating section for isolating the light from said light source unit orarray lens to the P-polarized light beam and S-polarized light beam anda converting section for converting the polarizing direction of any oneof the P-polarized light beam and S-polarized light beam of the lightemitted from said isolating section, whereby at least said first andsecond array lenses, said isolating section and said converting sectionare arranged in the manner that respective optical axes thereof arealmost matched with a line.
 30. Optical unit to form an optical imagedepending on a video signal by irradiating the display elements with thelight from the lighting optical system, said lighting optical systemcomprising an array lens having the structure that a first array lens tocondense the light from the light source unit to form a plurality ofsecondary order light source images and a second array lens to focus alens image of said first array lens to said display elements are usedand the diagonal size of the lens cell of any one or both first andsecond array lenses is set to almost 0.18 inch or less, a isolatingsection for isolating the light from said light source unit or arraylens to the P-polarized light beam and S-polarized light beam and aconverting section for converting the polarizing direction of anyP-polarized light beam and S-polarized light beam of the light emittedfrom said isolating section, whereby at least said first and secondarray lenses, said isolating section and said converting section arearranged in the manner that the respective optical axes thereof arealmost matched with a line.
 31. Optical unit to form an optical imagedepending on a video signal by irradiating the display elements with thelight from the lighting optical system, said lighting optical systemcomprising an array lens having the structure that a first array lens tocondense the light from the light source unit to form a plurality ofsecondary order light source images and a second array lens to focus alens image of said first array lens to said display elements are usedand the total number of any one or both lens cells of said first andsecond array lenses is set to almost 240 or more, an isolating sectionfor isolating the light from said light source unit or array lens to theP-polarized light beam and S-polarized light beam and a convertingsection for converting the polarizing direction of any one of theP-polarized light beam and S-polarized light beam of the light emittedfrom said isolating section, whereby at least said first and secondarray lenses, said isolating section and said converting section arearranged in the manner that the respective optical axes thereof arealmost matched with a line.
 32. Optical unit to form an optical imagedepending on a video signal by irradiating the display elements with thelight from the lighting optical system, said lighting optical systemcomprising an array lens having the structure that a first array lens tocondense the light from the light source unit to form a plurality ofsecondary order light source images and a second array lens to focus alens image of said first array lens to said display elements are usedand the lens focal distance of lens cell of said first and second arraylenses is set to almost 30 mm or less, an isolating section forisolating the light from said light source unit or array lens to theP-polarized light beam and S-polarized light beam and a convertingsection for converting the polarizing direction of any one of theP-polarized light beam and S-polarized light beam of the light emittedfrom said isolating section, whereby at least said first and secondarray lenses, said isolating section and said converting section arearranged in the manner that respective optical axes thereof are almostmatched with a line.
 33. Lighting optical system for an imagingapparatus to form an optical image depending on a video signal byirradiating the display elements with the light from the light sourceunit, comprising an array lens having the structure that a lens tocondense the light from said light source unit to form a plurality oflight source images is used and at least any one of the diagonal size,vertical size and lateral size of the lens cells arranged in a plane isset to almost 1/(4.5 or more) for corresponding each size of saiddisplay elements.
 34. Lighting optical system for an imaging apparatusto form an optical image depending on a video signal by irradiating thedisplay elements with the light from the light source unit, comprisingan array lens having the structure that a lens to condense the lightfrom said light source unit to form a plurality of light source imagesis used and a plurality of lens cells having the diagonal size of 0.18inch or less are arranged in a plane.
 35. Lighting optical system for animaging apparatus to form an optical image depending on a video signalby irradiating the display elements with the light from the light sourceunit, comprising an array lens having the structure that a lens tocondense the light from said light source unit to form a plurality oflight source images is used and the lens cells in the total number ofalmost 240 or more are arranged in a plane.
 36. Lighting optical systemfor an imaging apparatus to form an optical image depending on a videosignal by irradiating the display elements with the light from the lightsource unit, comprising an array lens having the structure that a lensto condense the light from said light source unit to form a plurality oflight source images is used and a plurality of lens cells having thefocal distance of almost 30 mm or less are arranged in a plane. 37.Array lens having the structure that a plurality of lens cells havingthe diagonal size of almost 0.18 inch or less are arranged in a plane.38. Array lens having the structure that lens cells in total number ofabout 240 or more are arranged in a plane.
 39. Array lens having thestructure that a plurality of lens cells having the focal distance ofalmost 30 mm or less are arranged in a plane.